I did a lot of research recently on ukes. I want one, but still have not purchased.
New ukes go from the $20 FirstAct at WalMart, up to the $2000 or more Martin. Pastor Gary is right about the Kamaka. It is the top brand, along with Martin. Martin ukes don't seem to loose any value. Older ones from the 1930's through the 1960's can bring more than a new one. If I were you, I would check the brand name on the old used one the lady tried to sell you for $100. Check ebay and see what the brand brings, could be an investment.
Lanikai is a more moderately priced uke that seems to get good reviews online. They are available at
www.musiciansfriend.com. Lanikai has decent models in the $80 to $300 price range. There are other good brands there as well. Ibanez and Fender make moderately priced ukes also.
From what i can tell, you have to get above $50 to get away from the "toy" ukes. Cheap ones will not stay in tune nor will they chord in tune on up the neck.
You probably won't find many in music stores....in the south anyway. Not a high volume seller. Online will be your best bet, probably.
Hope any of this helps.